Many processes and apparatus have been proposed for the lamination of glass. These include those disclosed in U.S. Pat. Nos. 1,667,832; 2,075,726; 2,088,776; 2,831,791; 3,132,581; 3,450,032; 3,518,137 and 3,654,039 which teach (among other process steps), the use of pressure gradients to eliminate air bubbles in the heated interlayer between the sheets of glass to be laminated (See U.S. Pat. Nos. 1,667,832 and 3,518,137) and the rearward expulsion of the trapped air from between the sheets of glass to be laminated (See U.S. Pat. No. 2,088,776).
A newer and less costly approach to the manufacture of laminated glass includes the irradiation of a thermoplastic film interlayer between the glass sheets for securing the glass sheets together.
However, none of the processes proposed is carried out simply, effectively, in minimal time, and at minimum cost. For example, while U.S. Pat. No. 3,518,137 teaches the use of a pressure gradient for expressing air bubbles from between the glass sheets, the sheets of glass require double processing to eliminate a gap formed between the glass sheets proximate one of the edges of the laminated sheets of glass during initial processing.
A similar gap is left between the sheets of glass when the process of U.S. Pat. No. 2,088,776 is carried out.
In the latest processes employing irradiation of a photopolymerisable liquid adhesive composition for securing glass sheets directly to one another or indirectly to one another employing a substrate between the glass sheets, additional and other problems present themselves, as for example, the expressing of liquid adhesive composition from between the glass sheets onto parts of the apparatus used in the process.
It is therefore, an object of this invention to provide simple, cost effective processes for the lamination of sheets of material, including sheets of glass, with and without a substrate or interlayer, which processes overcome the aforementioned difficulties and which processes lend themselves to efficient mass production of among other products, laminated glass.
It is a further object of this invention to provide apparatus suitable for use in such processes.
Further and other objects of the invention will be realized by those skilled in the art from the following summary of the invention and detailed description of embodiments thereof.